In order to obtain good performance in fiber optic connectors, the distal ends of the fibers terminated in a pair of mating connectors usually are maintained in physical contact with each other. The ends of the fibers conventionally are flat, polished and in abutment with each other to minimize transmission losses between the fibers. The fiber ends protrude slightly from components of the mating connectors, such as ceramic ferrules which embrace the fibers.
One of the problems in fiber optic connectors of the character described is to maintain a particular protruding length of the fibers beyond the connector components or ferrules. If the protruding end of a fiber is too long, the fiber can break due to high stresses created in the mated connectors. If the fiber protrusion is too short, physical contact between the fiber ends can be difficult, resulting in a decrease in performance/transmission quality, i.e. an increase in transmission losses. For instance, it has been found that fiber protrusion in a given fiber optic connector may be as small as in the 0.1 to 2.5 micron range, in order to establish a good physical contact between the abutting ends of the optical fibers.
Presently, there are no known instruments which can accurately measure such small protruding distances in production or field environments. Heretofore, laboratory-type equipment of a complex and expensive nature has been the only means known to perform such measurements. This invention is directed to providing a relatively simple apparatus for accurately measuring the fiber protrusion distances in conventional fiber optic connectors.